BACTERIA AND DISEASE 



385 



686. Effects of bacteria upon living bodies. Wherever 

 there is a moist cavity containing albumin, bacteria may 

 grow. The mouth is 

 usually swarming with 

 them, and may be offen- 

 sive from the decay 

 which they cause. They 

 also grow abundantly in 

 the intestine. A few 

 forms can grow in the 

 lymph spaces within a 

 living body. There 

 they form poisons called 

 toxins, which circulate 

 with the blood and pro- 

 duce various diseases, 



Bacteria growing in the mouth (x 400). 



The specimen was obtained by scraping a 



healthy mouth. 



a nucleus of an epithelial cell. 

 b different forms of bacteria. 

 c outline of an epithelial cell. 



such as erysipelas, diphtheria, typhoid fever, consumption, 

 cholera, lockjaw, and the grippe. Because these diseases are 

 always caused by germs which are planted in the body they 



are said to be infectious. 

 All diseases caused by 

 germs are infectious. 



Measles, scarlet fever, 

 mumps, whooping cough, 

 and smallpox also are due 

 to some influence from 

 without the body. This 



Bacteria growing in a kidney and producing 



an abscess (X 300). 

 a kidney tube. 



b white blood cell attacking bacteria. 

 c bacteria. 

 d blood tube of the kidney. 



room with a sick person, and so are said to be contagious. 



OV. PHYSIOL. 25 



influence 

 proceed 

 of germ 

 diseases can 

 by being 



is supposed to 

 from a kind 



also. These 

 be caught 



in the same 



